US1566756A - Ments - Google Patents

Description

Dec. 22 1925. 1,566,756

.1. N. MAHONEY HIGH TENSION SWITCH Filed June 14, 1921 2 Sheets-511.0% 1

. J. jrlvenior'.

Dec. 22, 1925. 1,566,756

J. N. MAHONEY HIGH TENSION- SWITCH Filed June 14, 1921 2 Sheets-Sheet 2 Patented Dec. 22, 1925.

UNITED STATES PATENT OFFICE.

JOSEPH N. HAHONEY, F BROOKLYN, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- IENTS, TO CONDIT ELECTRICAL MANUFACTURING CORPORATION, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

OF BOSTON,

HIGH-TENSION SWITCH.

Application filed June 14, 1921. semi No. 477,313.

- To all whom it may concern:

- Be it known that I, J osnrn N. MAHONEY,

a'citizen of the United States, residing at Brooklyn, in the county of Kings and State 1 of New York, have invented an Improvement inHigh-Tension Switches, of whic the following is aspecification.

especially adapted to control circuits of relatively high potential.

It has heretofore been commonpractice to employ'oil as the arc quenchingfluid; and oil is very satisfactory for quenching arcs formed by the interruption of circuits of relatively low potential and current. .With higher potentials and current,l however, it is found thatthe oil is broken downby the are into fixed combustible gase's' which collect in the ex ansion'space above the oil in 'fl so the switch an commingle withthe air therein to form a'highlyexplosive' mixture; and the mixture is frequently ignited b'yithe arc with diastrous results tov the'switch and' surrounding'objects. "Other'insula'ting and noncombustible larc'quenching fluids, as carbon 1 tetrachloride, have been suggested but it is f,found that suchsubstitutes are very volatileat the usual switch operating temperatures 7 and consequently, the switch freque'ntly" replenished. Furthermore, %l1ql11(lS such as carbon tetrachloride haveibut' relatively little heat capacity andjare easily va-,

porized by the heat of the arc;- and tlie gaseous pressure within the 'switchi'resulting from the copious and relatively, sudden vaporization of the liquid may equivalent,

in its efiects, to; an explosion pressure, and] damage the switch.

Oil also has but relatively-little heat ca 40 pacity and a considerable, am'ount ofoil is vaporized when the arc is drawn and be-' fore it is uenched and, if'ithegarc represents consi erable energy, arelatively 'large.

volume of oilvapor maybe generated and gaseous pressure will be built up withinthe switch.

An object of this invention is to provide a switch ada ted to interrupt circuits of relatively big potential and current.

v 1 from contact with the stationa This invention relates to electrlc switches In carrying out the invention, I preferably. arrange thestationary and movable switch members in such a manner that the stationary member is immersed below the surface of the arc, quenching fluid and the movable member is adapted to be withdrawn member and entirely out of and above t e surface of the arc quenching fluid. I It is also an object of the invention to provlde an arc quenching fluid characterized by having a relatively great heat capacity, high boiling point, vapors which are nonv combustible, or substantiallyv so when mixed 'w th air, and ordinarily not broken down into appreciable volumes of fixed gases by the heat of the arc. By reason of a high boilin point there will be but small lossof uid y' normal evaporation. Because of high heat capacity, which includes high specific heat of the liquid andheat of vaporization, avrelatively large amount of heat is required in the arc to vaporize the liquid in contact with the arc and consequently the arc will be cooled ra idly and the circuit interrupted with but little evolution of vapor.

By virtueof thatcharacteristic of the liquid by which" it is not broken down into fixed or permanent gases the collection of gas in the expansion space of the switch is obviated; and as the uses and vapors of theliquid are non-com ustible when mixed with the explosion is prevented.

'It is also an object of the invention to provide an arc quenching fluid that is weak 1y electrically conducting especiall when employed in a switch of the type a ve set forth.

ter has a highboiling point and hi h heat ca acity-whereby itis enabled to a sorb a re atively great amount of heat energy from the arc and quench it rapidl Its va ors are non-combustible and'it 15 not bro en down appreciably into combustible permanent gases by the heat of the are so that danger fromexplosion is obviated or arc quenching fluid having the characterlstics above enumerated is water. Wa-

air in theexpansion space the possibility of greatly reduced. It is weakly electrically conducting so that as the movable switch members is withdrawn an increasing resistance will be interposed gradually in the circuit and the current will be substantially lowered when the movable switch member is finally withdrawn above the surface of the liquid and the final interruption of the circuit is thereby facilitated; and the circuit may be int rrupted without setting up surges of appreciable magnitude. Furthermore, water vapor may have the property of being unidirectionally conducting, and as the final arc will be between the movable switch member and the liquid, the arc may be quenched at the end of the half wave.

A further object of the invention is to provide a switch wherein the arc may be blown out or quenched by expulsion and by the vapors generated bv the heat of the are; and

l a yet further object is to provide a switch with means, and preferably self-contained m'eans. arranged automatically to replenish the switch casing with are quenching fluid to make up for loss of fluid due to circuit interruption.

A further object is generally to improve the construction and operation of electric switches.

Fig. 1 is a side elevation, partly in section, of a switch unit embodying the invention.

Fig. 2 is a plan view of the switch of Fig. 1.

Fig. 3 is a sectional detail of the stationary switch member.

Fig. 4 is a planview of the switch member of Fig. 3. Fig. 5 is a sectional v ew of the cap for the switch tube.

Fig. 6 is a plan view of the cap of Fig. 5.

Fig. 7 is a sectional detail of the connection between the supply reservoir and the switch tube. 4

Fig. 8 is a plan diagram of a three phase switching arrangement.

Fig. 9 is a diagrammatic elevation of the switch ith the movable switch members arranged in switch-open position.

.As here shown the switch embodying the invention includes the switch casing 10 adapted to contain the stationary and movable switch members and the supply reservoir 11 formed preferably of a relatively thick cylinder of insulating material; and both are supported on the insulating base 12 which in turn is supported on the insulating pillar 13 The switch casing 10 comprises preferably a relatively thick cylindrical tube formed of a suitable insulating material, as micarta, and is relatively small in internal diameter as contrasted with its height for reasons hereinafter to be set forth. The

lower end of said tube is received the re- 55 cess 14 of the stationary switch member 15; and the side wall of said switch member is split whereby said sidewall may be clamped securely about the tube by the bolts 16. Said switch member also forms the bottom closure for the tube. Said switch member is formed with a laterally extended ear 17- by which the switch casing may be secured 'to' the base 12 in vertical position. The up adapted to receive the movable switch-mem 7 her including the rod 20. Said stationary switch member may be provided with suitable means, as the bolt 21,.byv which electric popnsction with a circuit lead 22 isBStab In practice two switch units will prefer-.

ably be employed to control a circuit, as one of the phases of a multihase line, and the units will be mounted si e by side as illustrated in Fig. 1 and spaced apart to provide adequate air insulation between them. I

The switch rods 20 of the units are secured to and depend from the cross-bar 25 which is preferably formed of wood and a jumper 24 is extended between said rods 20 to conmeet them electrically. Said cross-bar is secured to the insulating rod 26 which depends from the arm 27 of the switch 0 rating mechanism by which said rod is guided for vertical movement in a straight line.

When the switch is opened the switch rods 20, preferably are withdrawn entirely out of the casings 20 and to a suitable distance thereabove as illustrated in Fig; 9. While the casings may have open tops, I prefer to close the tops of the casings immediately after the withdrawal of the switch rods and provide means to control the direction of discharge of gas and vapor from the switch. For this purpose a cap 30 is secured over the top of each tube 10; and the side wall of the cap may be slotted and drawn'into firm engagement with said tube by the bolts 31. The top wall of the cap is formed with.

an aperture 32 therein through which the switch rod 20 is adapted topass and a plate 33 pivoted by the pin 34 to theunder side of the top wall of said cap is arranged to close said aperture when the switch rod is withdrawn and thereby prevent discharge of gas or fluid through the aperture. 1 A spring 35 normally tends to hold the plate over the aperture and said plate will be moved-from" its covering position by the switch rod when said rod is moved downwardly toward switch closing position.

Said tube 11 may be formed with an aperture 36 in its side wall and said cap maybe provided with a tubular recess 37 adapted to receive an insulating tube 38 in alignment with said aperture 36; and said tube may be secured frictionally in said recess by the bolts 39 which serve to draw the slotted side wall of the cap tightly about said tube 38.

Said insulating tube 38 may be extended to any desirable location for the discharge of vapors and liquid from the switch.

When the .switch is operated under severe electrical conditions there ma be a generation of vapor from the liquid in the switch and an expulsion of the vapor and some of the liquid from the switch and consequently the level of liquid in the switch casing may be lowered. The supply reservoir 11 is relatively large in dlameter as contrasted with the diameter of the switch casing 11 and is adapted to hold a relatively large amount of liquid with which to replenish liquid in the switch-casing and restore the liquid level therein nearly to its former level. Fluid communication between the reservoir and the switch casing is provided by the pipe 40 which preferably is formed of an lnsulating material, as bakelite, and which is extended between the reservoir and easing below the fluid level therein and preferably at the lower portions of said reservoir and easing. A check valve 41 is provided as a part of said ipe 40 by which flow of fluid from the switc easing into the reservoir is prevented while permitting free flow of fluid in the reverse direction. It will iii be obvious that, when the liquid in the switch casing 10 is lowered over that in the reservoir, fluid will flow through the pi e 40 and into the switch casing until the uid level in said casing and reservoir is substantially at the same level. Because of the relatively large fluid capacity of the reservoir as contrasted with the switch casing, said casing may be filled with fluid from the reservoir a considerable number of times without an undue lowering of the fluid level in the switch casing. When the fluid level in the reservoir has become low additional fluid will be supplied.

While the switch above set forth will function satisfactorily with any of the usual arc quenching fluids, I prefer to employ water as the arc quenching fluid, for the reason, as above set forth, that water has high heat absorbent capacity, is not easily volatilized, and its vapors are non-combustible when mixed with air. Consequently, the switch employing Water will have a higher interrupting capacity than when other fluids, deficient in one or more of the above enumerated desirable properties, are employed.

By reason of the relatively small diameter the are by expulsion.

ol' the switch casing 10 as compared with its length it may have several methods of operation. For moderate current values the high resistance of the water may serve to reduce the current flow gradually when the switch rod is withdrawn and without the formation of an are between said rod and the switch casing from the reservoir to restore the fluid level in the casing nearly to its former level. For yet heavier currents such a heavy arc may be drawn between the switch rod and] stationary contact member that a large volume of water is vaporized by he heat of the arc and the water vapor will be forced upwardly in the casing with practically explosive violence and quench As previously set forth, I prefer to employ two switches to form a unit as illustrated in Fig. 1 to control a circuit and for a three phase circuit three units will be employed, as illustrated in Fig. 8. Preferably each unit and each switch of a 'unit will be spaced apart to provide adequate air insulation between them and in addition insulating barriers 50 and 51 will be interposed between the switches and the units and extend a substantial distance above the switches whereby to provide -additional sulation.

It will be obvious that the invention'may be embodied in modified structures without departing from the spirit thereof.

I claim: I

1. An electric switch including a relatively long and narrow upright tube adapted to contain a relatively long and slender column of arc-quenching fluid for'the major portion of its height and havinga vent to the atmosohere above the long fluid column, relative y separable switch members disposed in said tube beneath the fluid and arranged for separation adjacent the bottom of the column and in the direction of the length of said column. and means to maintain said column of fluid in said tube including a reservoir adapted to contain asupply of arc-quenching fluid and open to the atmosphere and disposed at said tube and extended approximately co-extensive the length thereof. a conduit in communication with the interior of said reservoir and tube below the fluid levels therein, and a fluidactuated valve in said conduit arranged to permit fluid to flow from said reservoir into said tube and to prevent fluid flow in the reverse direction.

2. An electric switch including a relatively long and narrow upright tube adapted to contain a relatively long and slender column of arc-quenching fluid for the major portion of its height and having'a vent to the atmosphere above the long fluid column, relatively separable switch members dlsposed in said tube beneath the fluid and arranged for separation adjacent the bottom of the-column and in the direction of the length of said column, and means to maintain said column of fluid in said tube including a reservoir adapted to contain a supply of arc-quenching fluid and open to the atmosphere and disposed at said tube and extended approximately co-extensive the length thereof, a conduit in communication with the interior or said reservoir and tube below the fluid levels therein, a fluid actuated valve in said conduit arranged to permit fluid to flow from said reservoir into said tube and to prevent fluid flow in the reverse direction, a support common to both reservoir and tube, and an insulating pedestal for said support.

An electric switch including a switch casing comprising a tall and narrow tube having side walls formed solely of insulat ing material, and adapted to contain the stationary and movable switch members and a relatively slender column of electrically conducting arc-quenching fluid, a reservoir for a supply of conducting arc-quenching fluid disposed approximately co-extensive the length of said tube and having its side walls formed solely of insulating material, said reservoir arranged at one side of and adjacent said switch casing, a conduit in communication with the interior of said reservoir and switch casing below the fluid level therein, and a fluid-actuated valve in said conduit. I 7

4. An electric switch including a casing adapted to contain an arc-quenching fluid,

a stationary switch member disposed beneath the level of fluid in the casin a movable switch member comprising a rod adapted to be extended through the top of and into the casing to complete the circuit through the switch and be withdrawn above the fluid level and entirely out of the casing to interrupt the circuit through the switch, and means to close the top of the casing above the fluid level automatically upon the withdrawal of said rod from the casing.

5 An electric switch including a casing adapted to contain an arc quenching fluid and an expansion space above the fluid, a stationary switch member disposed beneath the level of the fluid in the casing, a switch rod movable in and out of the casing, a cover for the to of the casing and the expansion space aving an aperture therethrough through which said switch is adapted to be extended, and a valve yleldmgly closing said aperture.

6. An electric switch having a casin adapted to contain an arc quenching flul and a gas expansion space above the fluld, a stationary switch member disposed beneath the level of the fluid in the casing, a switch rod movable in and entirely out of the easing, a co"er for the top-of the casing and the gas expansion space having an aperture therethrough through which said switch rod is adapted to be extended, a valve removably closing said aperture, and a vent passage arranged to establish communication between the. expansion space and the exterior of the switch.

7. An electric switch having a casin adapted to contain an arc quenching flui l and a gas expansion space above the fluid, a stationary switch member disposed beneath the level of the fluid, a switch rod movable within the casing, an end cap forming a cover for the top of the casing and the gas expansion space havin through which the switch ro is adapted to pass, and a laterally-extended conduit carried by said cap and arranged in communication with the expansion space beneath said cover.

8. An electric switch having an insulat ing tubular casing adapted to contain an arc quenchin fluid and a gas expansion space above t e level of the fluid, a switch rod movable in and entirely out of the easing, an end cap forming a cover for the top of the casing having an aperture. therethrough through which said switch rod is ada ted to ass, said end cap havin a side we] exten ed downwardly over t e side wall of the casing, and an aperture in its side wall, said casing having an aperture in alignment with the aperture in said end cap, and a conduit of lnsulatin material received in the aperture in sai end cap throu h which the switch is vented 9. Kn electric switch including a casing adapted to contain an arc-quenching fluid; a stationary switch member disposed beneath the level of the fluid in the casing; aswitch rod movable in and out of the casing; means to close the top of the casing automatically upon withdrawal of said rod from the easing; a reservoir for arc-quenching fluid arranged for fluid connection with the interior of said switch casing, a conduit conmeeting the interiors of said reservoir and casing, and a fluid-actuated valvein said conduit.

10. An electric switch including a casing adapted to contain an arc-quenching fluid and an expansion space above the fluid, a stationary switch member disposed beneath the level of the fluid in the casing, a movable switch member, comprising a rod, adapted to 1 an aperture be extended through the top of and into the casing and be withdrawn entirely out of the casin to interrupt the circuit through the switch; a cover for the top of the easing having an aperture therethrough, through which said switch rod is adapted to be extended; a valve yieldingly closin said aperture; a separate reservoir adapte to contain a supply of arc-quenching fluid, arranged contiguous said switch casing and 10 a valved conduit in communication Wlth the interior of said reservoir and easing below the fluid level therein.

In testimony whereof, I have vsigned my name to this s ecification.

JESEPH N. MAHONEY.

Images